HOW TO ADD FRACTIONS
Introducing:
•first addend
•second addend
•sum
Add Fractions 1
This picture shows an addition example with two addends and a sum. The
first addend 1/5 is combined with the second addend 3/5 to give the sum 4/5.
Notice how the sum 4/5 is combines the red 1/5 with the blue 3/5.
Add Fractions 2
1/
5
and 3/5 are like fractions because the denominators are the same. When
the addend denominators are the same, add the numerators to get the
numerator of the sum.
Add Fractions 3
The sum 12/8 is written as a mixed number 1 4/8 and is then written in
lowest terms. The numerals 12/8 , 1 4/8 and 1 1/2 are all correct names for
the sum of 5/8 and 7/8.
Add Fractions 4
Here, mixed numbers are added. The whole number 1 in 1 3/5 is added to
the whole number 2 in 2 1/5 for a whole number 3 in the sum. The
fractions 3/5 and 1/5 are added for 4/5 in the sum.
Add Fractions 5
The same example 1 3/5 plus 2 1/5 is shown with number lines. Add the
whole numbers and then the fractions:
1 3/5 + 2 1/5 = (1+2)+ (3/5 + 1/5) = 3 4/5.
Add Fractions 6
This example shows the sum 3 5/5 written as 4. Since the fraction 5/5 is
equal to 1, 3 5/5 is equal to 3 + 1 for a sum of 4
Add Fractions 7
This example shows the sum 3 7/5 written as 4 2/5. The 7/5 part of the sum
can be renamed as 1 2/5 . The 1 in 1 2/5 is added to the whole number 3 for
the 4 in 4 2/5:
1 3/5 + 2 4/5 = 3 7/5 = 3 + 1 2/5 = 4 2/5.
Add Fractions 8
The addends 2/3 and 3/5 are unlike fractions. Each addend is written with
the common denominator 15 before the numerators are added, giving a
sum of 19/15 or 1 4/15.
Add Fractions 9
The unlike fractions 21/4 and 12/3 are renamed as like fractions 23/12 and 18/12.
Then the whole numbers and numerators are added for a sum of 33/12.
Add Fractions 10
Write each addend with a common denominator 12. Because 17/12 can be
written as 15/12, we can write the sum 4 17/12 as 5 5/12.